This invention relates to gamma cameras by which studies can be performed that produce diagnostic images using radioisotopes and, in particular, to gamma cameras which provide the ability to modify the parameters of a study while the image data is being acquired.
In preparing for a nuclear medicine study the clinician will spend time setting up the nuclear camera so that it will proceed through the sequence of steps needed to carry out the study. During the setup procedure the clinician will establish parameters which govern the study, such as the time during which emission events are acquired, the number of image frames that will be acquired and produced, and the number of event counts minimally required to produce a reliable image. After all the necessary parameters have been set and the patient has been prepped, the examination will begin and the gamma camera executes the study defined by the parameters. The study is concluded when the gamma camera has performed the procedures governed by all the parameters.
However, as the study proceeds the clinician may observe that the data is not being acquired as anticipated. The uptake of the radioisotope by the body may not be proceeding as rapidly or as slowly as expected, for instance, or the washout of the radioisotope from the region of interest may not be proceeding at the rate anticipated. In such cases the images produced may be inadequate to make a definitive diagnosis. Now armed with this experience, the clinician will generally conduct a second study using parameters which accommodate the shortcomings of the first study. In doing so the clinician must hope that the physiological conditions experienced in the first exam will be repeated so that yet a further imaging session is not required. But the second study may disrupt the scheduling of patients for the camera, may require a second appointment by the patient, and exposes the patient to the radioisotope a second time. It would be desirable to prevent these difficulties by enabling the clinician to react during the study so that corrections in the study protocol can be made while the study is in progress and the need for repeat studies prevented.
In accordance with the principles of the present invention, a gamma camera is provided in which the study protocol can be modified after the study has commenced and while event data is being acquired. In such a camera study parameters such as the duration of the study, the number of image frames acquired, or the count criterion required to produce an image may be changed as the study proceeds. Thus, a nuclear study which is seen to be leading to unsatisfactory or less than optimal results may be altered during acquisition to increase the likelihood that diagnostically useful results will be produced.